Hello Mono1989,
Sorry I saw your post a bit late, but anyway, if you haven't had your assessment, its all easy, from memory, you got the ticket checking test, which you have to check tickets in a set time limit as accurately as possible, they look identical to the ones you will check on the job. There is only 3 things to really worry about, date, time of day and destination. If one or more don't match up, you reject the ticket with the code.
The other test I think is just a verbal test, it tests you ability to understand and follow commands. Don't be ashamed to read the passage more than once as you might need to. There is no mathermatics involved as far as I know of and thats it.
If you are successful, you will be given an interview with one of the Station Managers (Flagship and Duty IIRC - usually 2 of them), then a medical, then induction (for 2 days), then training for 5 days and it will take you about 3 weeks to go from training to operating a gateline.
(I know, as I went for the Haslemere position and I've currently just gone through the training, I'm in week 2 of 3 at the moment and since I've already worked a gateline, then it reduces my training.)
Since I have just gone through the recruitment process, please do ask.

PM me and I'll see if I can help.